Rotary engine.



C. H. CLARK.

ROTARY ENGINE.

APPLIOATION FILED MAY 26, 1909.

Patented Apr. 8, 1913.

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C.H.GLARK. ROTARY ENGINE.

APPLICATION FILED MAY 26. 1909.

Patented Apr. 8, 1913.

4 SHEETS-SHEET 2 C. H. CLARK.

ROTARY ENGINE.

APPLICATION FILED MAYZG, 1909.

1,058,153. Patented Apr. 8, 1913.

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G.H.GLARK. ROTARY ENGINE.

APPLICATION FILED MAY 26, 1909.

Patented Apr 8, 1913.

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owners is. CLARK, or can :snanorsoo, canrronnm, Assmnon 'ro srannnnn GEAR moron COMPANY, or rnonmx, ARIZONA,-A conroaa'rron or ARIZONA.

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Application filed may 26', 1909. Serial No. 4 98,579.

Patented Apr. a, 19-13.

To all whom it may concern Be it known that I, CHARLus-.H. CLARK, a citizen of the United States residing in the city'and county of San Francisco-and State of California, have invented a new and useful Improvement in Rotary Engines,

and are propelled by the pressure of a corn.

fined fluid and not by its impact The engine is not of the impulse type for the teeth are not used as vanes wherein a jet of fluid is directed to strike against them as in a turbine engine. 2O

The engine has for its object to provide an improved motor of the character stated,

having means for running at high speeds and under high pressures, as well as under low speeds and pressures, for keeping the gears in alinement in any position of the engine, which may be regulated by the braking action of a retarded exhaust, which may be operated by superheated steam or bycold fluids, which may be reversed without altering the adjustment of the centerpiece to the gears, which may have the directions of the entering fluid and discharging fluid in line with the direction they must follow in the.

engine, and wherein the centerpiece can be adjusted to the sides and curved faces of the gears before being clamped in place.

Another object of my invention is to pro vide a, combination fluid pressure engine and pump. 3

Another object of my invention is to probe used as a pump.

Another object of my'invention is to provide in a device of the character described means for compensating the thrust on the bearings.

Another object of my invention is to provide a device of the character referred to, and means for compounding the .s

vide' a motor that in its various forms may- Qther obj-cots will appear in the following description and claims.

I attain my objects by the means illustrated in the accompanying drawing of which:

Figure 1 is a side elevation of my engine in its simp est form; .Fig. 2, a side elevation of my engine incasedyFig. 3,41. horizontal central section through case of Fig. 2; Fig. 4, an and elevation of Fig. 2, showing pulley inside the bearings; Figs. 5 to 12 inclusive are detail views of my centerpiece and parts thereof showing modifications for various uses; Fig. 13, a diagrammatic view of the piping ordinarily used in my device in connection with mycenterpiece, showing pipe utilized to exhaust the main partof the fluid from any part of the outer inclosing case shown in Figs. 2, 3 and 4; Fig. 14, a fragmentary, enlarged View of the gear- ,wheels about their point of intermeshing;

Fig. 15, a diagrammatic view of the piping for use with the centerpiece of the type shown in Fig. 10; Fig. 16, a diagrammatic view of .the piping for compounding a number of my engines; Fig. l7 isa vertical sectional view of my engine taken through the line w-y, Fig. 18; and Fig. 18 is a longitudinal central sectional view showing a moditied form of case. The same numeral of reference marks the same part throughout the various views.

My inventionconsistsin the novel parts, combinations and arrangements set forth in the followingdescription and particularly pointed out in the claims.

Explaining my invention in detail, and referring to the'drawings, I- provide a pair desirable that the. friction be reduced to aminimum;-and I attain the desired result not-only by making my gear teeth 7 roletively'small, but by leaving a clearance space between the sides of mygears and the inclosingstructure, inthe manner furtherdescribed below.

Another reason for making the teeth small is that the space betweenthe teeth is thusmade but very little larger than the area. of the tooth itself. As the sizeof the teeth is increased in comparison to the diameter of the gear, the space aforesaid becomes so large relatively to the teeth that the engine is not economical; for to be economical and theoretically perfect the area of the space shouldequal the area of the tooth. 1

In devices of the character specified,-friction plays an important partin their operation, especially when they are operated at high speeds. The friction between the teeth themselves I diminish as aforesaid; but in. similar devices hitherto, there has always been provision made for side and face contacts between the gears and the inclosing block, to avoid the leakage of steam, when the fluid medium happens to be steam, along the sides and irontsof the ears. I further diminish the friction inci ent to said engines, by removing the side and face frietion altogether, by leaving a clearance space between the sides and faces of the gears and the inclosing block. This I find can be done and economically done at high speeds.

For the rapid rotation of the teeth creates a line of much. less resistance alongtheir course than :ists along their sides and faces if the clearanceis not more than say from one to three 'one-thousandths of an inch.

In combination with the gear wheelsv aforesaid I provide a centerpiece 8, which may be made in various forms but which possesses these most important features; that it is alwa s stationary, immovable, and rigidly secured, nent adjustments for running my engine at high s eeds; and need not be moved to reverse t e motor; that it allows the exhaust to be used for compensating the thrust on the bearings; that it allows several engines to be compounded and that it can be adjusted to the curved faces of the gears before being clamped.

Looking at Fig. l, which shows the uninca'sed type of my device, it will be seen and this allows fine permaantenna that there is a one piece casting 9, which is the, same, on each side of the gear wheels, and holds the complete engine together. By means of the bolts shown therein: the whole frame 5 and centerpiece 8 become like one solid block; and the machine can be operated. whether it is lying on its side or standing upright, without the centerpiece losing its alinement, as would not be the case with similar machines using steam balanced side walls. For such walls would be forced a ainst an-uneven surface by the weight -0 the gears and this would cause a. serious leak. v

In the centerpiece illustrated in Fig. 1, the entrance port for thefluid pressure is shown at 10, which is situated a little below the line joining the centers of the two gears. By this arrangement a downward pressure is exerted on the teeth below it, and an upward pressure on the teeth above, as is apparent from Fig. 14. The force acting on the gears is proportional to the pressure into the area of the teeth acted on; and as one tooth of one gear is always covering one tooth of the other gear above the entrance port, the. covered tooth is vnot acted on by the pressure. Consequently the downward pressure on that gear is not balanced by an upward pressure, as it is on the gear having the tooth in the lower or covering position, and it is therefore moved downwardly. The force moves from one gear to the other as the gears rotate, alternately back and forth, and

produces a continuous rotation. The plate 1-1, see Fig. 7, and the back 49 of centerpiece 8, see Fig. 8', are disposed closely against the sides of the gear wheels, leaving a clearance of from one to three one-thow sandths of an inch as aforesaid.

The fluid escapes directl into the air or into a receiver. Now, in t eir rotation, the gear teeth gatherair about the region above the meshing point; and this air they compress as they move downwardly, thus producing a retarding client on the engine. To

avoid this efiect- I provide an escape port- 12 in either or both the front and back of my centerpiece through which the air may escape. v

Attention is now directed to the block 13, forming part oit mv centerpiece. The function of said block is to create with the ront and back of the centerpiece and the bot oms of the spaces between the gear teeth, curved channels for directing the fluid pressure against the teeth, with or without exhaust ports withln the'cente'rpiece. The blocks are formed integrally with the centerpiece, but for the reasons aforesaid, they do notquite touch the faces of the teeth, the necessary adjustments beingmade by means of the bolts 14 and 16. Bolts 15 passing throu h the blocks and the front and ack of the centerpiece, and through the frame when in cased secure the whole in a rigid state, which may be made accurate in position with respect tov the sides of the gears by means of the thin metal adjusting sheets 17, 18. Any of the types of centerpiece shown in the drawing may be used in either the inclosed or uninclosed form of my engine. But where reversals are desired a double block may be used, one above the line of gear centers and one below it, forming two sets of channels, an upper and lower, as shown in Fig. 18. By the described arrangement I provide means for reversing my engine without moving the centerpiece; and an immovable centerpiece is necessary, especially for high speed machines, since the adjustments to avoid friction on the one land and leakage on the other must be very ne.

It is to be understood that reversals may be made by putting pressure in the case even where only one block is used; but such proceedin is attended with the disadvantage that if any play exists on the bearings,

the gear'locks on the centerpiece, and the case would have to be unduly heavy to stand the pressure. Therefore, two blocks are used as stated, and the gear wheels turn with equal -efliciency in either direction.

Referring to the means for brakin my engine. This is done by partially or w olly closing the exhaust port. Whenever the exhaust port is partially closed, said exhaust port being the entrance port of the reversal pressure, as by the valve 27 for instance, the pressure in the centerpiece rises and the force acting on the gears is lessened, since that force is equal to the difi'erence between the pressure at the entrance port and pressure inside the centerpiece.

While under certain conditions it is'not necessary to cause the fluid to enter and discharge without abruptly altering its direction in the engine, under conditions of high speed it is extremely expedient that it do so. The entrance and exhaust ports in- Fig. 1 show how the pipe 10, carrying the entering fluid and the discharge pipe p are in line withthe direction that the fluid must follow in'the engine.

My engine can be operated as a combined pump and motor. This is done by simply;

immersing vthe engine in the fluid to bepumped, using the double block, The driv ing fluid is introduced in the usualmanner at the entrance port on the opposite side of the meshing point of the two gears. The

operating fluid pressure escapes into and outof the liquid to be pumped and the gears force theliquid into the other ort and raise it continuously to any desire height.

Referring now especially 'to be inclosed type of my engine and looking at Fig. 2

and 3. It will be observed that my me ferred type of case consists of three parts 19, 20 and 21. Part 19 incloses the back, side, bottom .and top of my engine. The three parts of the case are suitably bolted together.v Another type of case is shown in Fig. '18. This type has a reinforcing rib 50 running entirely around it, formed of flanges on the upper and lower parts, bolted together. The top of the case lifts up and the gear wheels on each shaft can be atpressure fluid. The fluidenters the engine at the port 10 and passes through these channels. The exhaust'takes place in two Ways either through the exhaust port 22 (Fig. 18) situated near these channels and communicating therewith; or into the case and out at the opposite port 26, that is to say, the port that becomes the entrance port on reversal. In the latter arrangement part of the pressure goes out at the usual exhaust port near the channel and part remains in the case creating therein a pressure which has an important function. It will be noted that the pressure after entering and while in the channel exerts a thrust on the bearings which thrust must ordinarily be resisted by the strength of the bearings; but by providing a pressure in the case a re sultant pressure is produced which acts on the bearing in the opposite direction and with nearly equal force to the pressure from the channels, thus counter-balancing the thrust on the bearings. Explainin this counter-balancing effect more in detall', the fluid entering by way of the port'10,'F-.ig. 18, exerts a pressure on the gears until relieved by the escape of the fluid through the channels or passages 22, 22 into the ex- I the upper block 8, thereby aiding in revolving the gears. It will therefore be seen that the pressure in the casing, produced 10 throttling the exhaust ort 22, is not a bac pressure, in the sense t at it retards or impedes the rotation of the gears. In fact, throttling the exhaust port 22 has the eifect of dividing t-he-pressure fluid: part having a propellingaction on the gears on one side of the line joining their centers and the other part having a propelling efiect on the other side of said center line. The ports 10 and 26 may therefore be appropriately termed drivin ports, since the fluids pass: ing through t 'em act to propel the gears. At the same time this last port exerts on the gears a thrust in a direction substantially opposite to that produced by the other port; the resultant or ultimate thrust on the gear bearings being the difference between the two thrusts. In order, however, to have the internal pressure exerted in a counterbalancing direction the pressure fluid must escape nto-the casing at points less than 90 from the aforesaid center line and must enter the teeth again at points less than 90 This means thatin theconfrom said line. struction illustrated in Fig. 18 the edges 8, 8', must be lessthan 90 below, and the edges 8, 8 less than'90 above, the center line; the centers or apexes of these arcs or angles being at the axes of the gears. It'is also essential that the side walls of the in closing centerpiece be stationary or immovable so that the pressure in the casing cannot press either wall againstthe adja gines, the pipe line shown in 16 and the connections therewith are arranged as shown and specified. The exhaust from the first engine passes through pipes 31, 32 and 46; that from'31 entering, the second engine through valves and 35 into port 10 and passingtherefrom through pipe 36 into the airor condenser through the pipe 37 also through pipe 3'8 valve 35 pipe 39 valve 4Q pipe 43 into'port 10 of 'thethird engine and passing therefrom through pipe 48 into the air or condenser also through port 26 pipe 44 valve 40 and pipe 45 intothe air or.

condenser. Another portion of the exhaust fromthe first engine travels direct therefrom into the-third engine through port 10 in the followingmanner; through pipe 32 and into the air through fen'it is.desi.red to compound my en- Locate valve 41 pipe 42where it mixes with exhaust from the second engine andenters valve 40 pipe 43 into port 10 asbefore stated.

The second and third engines are progressively increased in size in their proper ratio.

Steam orother expansive fluid pressure me-. diums, may thus be used expansively. The

engines may be compounded in the ordinary way of carrying the fluid direct from one to the other; but the above described mode of compounding hasadvantag'es, among which is the fact that each engine is connected with a condenser and not only receives added power therefrom but it will be noted theta considerable portion of thefluid pressure is expansively used through several stages in each engine and exhausted directly into. air or condenser wherefore it is not'nece'ssary to construct the intermediatdpr" low engine nearly so large as would ordinarily be the case where the steam is carried di- "rectly from one to the other. itis possible to compounda gear-engine ofthi's f type and yet have noback pressure what- I ever on either the high or intermediate cylinder. All the gearsmay be mounted onfthe same two shafts having teeth of a different depth or gears of a difl'erent width, or they may all be mounted on one shaft having gears of a difierent diameter as well as width, or they maybe all allpwcd to independently of each other at any desired speed.

Returning now to .the consideration of [the forms of my centerpiece and their. parts illustrated in Figs. 5 to 12 inclusive, willbe noted that my centerpieceis' made up of two'partS, front 11 and a back49Q The front illustrated-in face view in Fig. '4 is attached to the back by appropriate screws or bolts, as indicated in Flg. 8; The use of the escape port 12 in the'flont and back plates has already been explained. 5

shows thelback plateus ed where it is not desired to reverse the engine, and'where' the exhaust takes place directly from the/centerpiece into the Fig. Gishpws aside view of such construction, 22 belng the exhaust pipe. Inthe' back shown in Fi '8,

theexlia ust takes'place from the ends 0 t as steam channels and not through the block 13. Fig. 9 is a side view of the centerpiece arranged in this manner, the pipes. shown therein illustrating the mode of introducing the p s r fluid t r u h b h the are andbackplatesfi 'UU F s- 10 s a ba k pl te n tru d n the mannershown in side view of Fig.15. It is designed fora double block, the front plate being shaped as illustrated, the joints occurring at 17 and 18.

Fig. 11 illustrates the manner in which thefluid .is introduced and exhausted-in line with the course it takes in the centerpiece.

The same figure illustrates a construction in which both the blocks 13 and 13 are made integral with the back plate, 49 and frame 5 or 6; 49' showing the combined back plate and frame. In such construction my gear wheels are adjusted to blocks Band 13. by means of adjustable bearings.

Fig. 12 illustrates the front or back plate shown in Fig. 13,- which in this construction are the same provided each one has the ports through it.

By the words immovable, stationary and like term applied to the centerpiece or parts thereof in the following claims I do not mean that such elements are necessarily non-adjustable, or non-detachable, but, in general, that they are rigidly fixed in position to the extent that they cannot be moved or shifted by the pressure or impact of the teeth channels for directing the pressure fluid against the teeth of said gear-wheels,

and a frame for supporting said centerpiece.

3. A gear motor comprising intermeshing gear wheels, an immovable centerpiece inclosing the parts of said gearwheels adjacent to their meshing point, a block fixed in said centerpiece on one side of said meshing point having curved faces adapted to form with the sides of said centerpiece and the bottoms of the spaces between the gear teeth channels for directing the pressure fluid against the teeth of said gear wheels, and having an entrance port for the pressure fluid, a second block on the other side of said meshing point fixed in -said centerpiece and having similar curved surfaces similarly adapted, and having an entrance port for the fluid pressure; and a frame for supporting said centerpiece.

,4. A gear motor comprising intermeshing gear wheels, an immovable centerpiece inclosing the parts of said gear wheels adjacent to their meshing point, a block fixed in said centerpiece having curved faces adapted to form with the sides of the centerpiece and the bottoms of the spaces between the gear teeth channels for directing the pres-- sure fluid against the teeth of said gear wheels, and having an entrance port for said pressure fluid and an exhaust port therefor on' the same side of the said meshing point, and a frame for supporting said centerpiece;

5. A gear motor comprising intermeshinggear wheels, an immovable centerpiece inclosing the parts of said gear wheels adjacent to their meshing point, and having 7 channels for directin the pressure fluid against the teeth of said gear wheels, and a combined supporting frame and inclosing case for inclosing said centerpiece and gear wheels and for supporting the same.-

6. A gear motor comprising intermeshing gear wheels, an immovable centerpiece inclosing the parts of said gear wheels'adjacent to their meshing point, a block fixed in salId centerpiece 'havln curved faces adapt.-

ed to form with the si es of said centerpiece and the bottoms of the spacesbetween the gear teeth, channels for directing the pressure fluid against the teeth of said gear wheels; and a combined supporting frame I and inclosing case for inc'losmg said centerpiece and gear; wheels and for supporting the same.

7 A gear motor comprising-intermeshing i gear-wheels having journals, a frame supporting said journals, a centerpiece rigidly E bolted to said frame, inclosing the parts of ?said gear wheels adjacent to their meshing point, and a fixed block in said centerpiece ,having curved faces adapted to form with the sides of said centerpiece and the bottoms of the spaces between the gear teeth, channels for directing the pressure fluid against the teeth of said gear wheels.

-8. A gear motor comprising intermeshing gear wheels, an immovable centerpiece inclosing. the parts of said gear Wheels adjacent to their meshing point, an inclosing .case, and means for operating said gear wheels and counterbalancing the thrust on their bearings, consisting of a, block fixed in 1 said centerpiece having curved faces adapted jto form with the sides of-said centerpiece and the bottoms of the spaces between the .teeth, channels for directing the pressure 'fluid against the teeth of said gear wheels, and having an entrance port for the fluid pressure and, a partially closable exit port therefor adjacent thereto, whereby when said exit portis partially closed, the pressure rises 'in the case and acts oppositelyv on the bearin S ta the action of the fluid pressure in said channels.

9. A gear motor comprising a frame, in-

termeshinggear wheels and means for ap-' plying fluid pressure to said gear wheels consisting of a front and back late rigidly bolted together and rigidlyv fixed to the frame, and having an escape port on one,

side of the intermeshing point, each of said plates being adjusted to leave a small clear ance between itself and the sides of the gear wheels; a block having curved faces conformable to the faces of the gear teeth and adjusted to leave a small clearance therebetween, and having an induct port on the other side of the intermeshing point.

10. In'a gear-motor, apair of intermeshing gear wheels, curved channels for directing the fluid pressure against the teeth thereof, and means for introducing and exhausting said fluid pressures consisting of pipes arranged substantially tangentially to said curved channels.

11. A gear motor comprising intermeshing gear wheels and rigidly fixed means for delivering and exhausting a fluid pressure medium to and from said geanwheels having a portion about the region of intermeshing in proximate contact with the sides and faces of said gears, and a portion away from said region spaced away from the sides and faces of said gears.

12. In a gear motor, rigidly fixed means for delivering and exhausting a fluid pressure medium to and from sald gear wheels having a relief opening and having a portion about the regionof intermeshing iii proximate contact with the sides of "said gears, and a portion away from said region spaced away from said gears.

13. A gear motor comprisin intermeshing gear wheels, a centerpiece mclosing the parts of said gear wheels adjacent to their meshing point, an inclosing case, and means i for operating said gearwheels and counterbalancing the thrust on their bearings consisting of a block fixed in said centerpiece having curved faces adapted to form with the sides of said centerpiece and the bottoms of the spaces between the teeth, channels for directing the fluid pressure against the teeth of said gear wheels, and having an entrance port for the fluid closable exit port t erefor adjacent thereto, whereby when said exit port is partially closed, the pressure rises in the case and acts oppositely on the hearings to the action of the fluid pressure in said channels.

14:. In a gear motor having a centerpiece, meansfor accurately adjustingthe position of said center iece consisting of thin metal strips located etween the joints thereof.

15. A gear motor comprising intermeshing gear wheels, and an inclosing case, a plate in proximate contact with the sides of said gear wheels about the region of their intermeshing, having a portion arranged for delivering and exhausting a fluid ressure medium to and from sa d gear w eels in proximate contact with the other sides and the faces of said gear wheels about the region of their intermeshing, and a portion pressure and a partially accents away from said region spaced away from both the faces and sides of said gear wheels. 16. In a gear motor, the combination of intermeshing gears; an inclosure for the gears, provided withstationary walls closely adjacent to the faces of the gears about the point of intermeshing, and provided with driving ports for the driving fluid on opposite sides of the line joining thecenters of the gears and with an exhaust port; and blocks arranged on opposite sides of said line between the said walls and forming in conjunction with the gears pairs of channels for the drivin fluid one pair of channels delivering flui' into the inclosure at points less than 90 from said center line and the other pair receiving fluid from the inclosure at points less than 90 from said line. Y

17. In a gear motor, the combination of intermeshing gears; a casing inclosing the gears, having an exhaust 'port-and having drivin ports for the driving fluid on opposite si es of the lines joining the centers of the gears; and a centerpiece comprising stationary side walls inclosing the gears about the point of intermeshing, and blocks on oposite sides of the said line, forming in conunction with the gears pairs of channels for the driving fluid, one pair delivering fluid into the casing at points lessthan 90 from said center line and the other receiving fluid at points less than 90 from said line.

18. In a gear motor, the combination of intermeshing gears; a centerpiece inclosing the gears about the point of intermeshing, comprising stationary side walls on the opposite sides of the gears and blocks on opposite sides of the line joining the centers of the gears, said blocks being formed with ourvilinear faces forming in conjunction with the gears channels for the driving fluid terminating at points less than 90 from the said, center line; and an inclosu're for the whole, having an exhaust ort; a port between one of said blocks'and said center line to deliver driving fluid to the gears andfa port between the other block and said center line to discharge driving fluid from the gears.

intermeshing gears; an inclosure for the gears having an exhaust port and having rivin ports for the driving fluid on opposite si es of andclose to the point of intermeshing of the gears; and a center piece inclosing the gears about the point-of intermeshing, composed of parts incapable of be ing moved by the driving fluid and constructed to deliver driving fluid into and receive driving fluid from the inclosure at points less than90 from the line joining the centers of the. gears.

-20. In arotary en' ine, the combination of intermeshing gear w eels; and a centerpiece 19."In a gear motor, the combination of mes es having normally fixed parts incapable of-being movedby the fluid supplied to drive the means for directing the driving engine, closely inclosing the gears about the point of intermeshing and at other points leaving space around the gears for free movement of the driving'fiuid.

21. In a rotary engine, the combination of intermeshing gears, and a combined centerpiece and frame, a portion of the centerpiece being detachable and adjustable with respect to the gears for the purpose set forth.

22. In a rotary engine, the combination of intermeshing gears; an inclosing case one side of which is closely. adjacent to the sides of the gears around their point of intermeshing; and a member on the opposite side of the gears, adjustable with respect thereto and incapable of being moved by the driving fluid.

23. Ina rotary engine, the combination of intermeshing gears; walls inclosing the sides of the gears adjacent to their meshing point; and adjustin sheets for accurately spacing said walls wlth respect to the sides of the gears.

24. In a gear engine, thecombination of intermeshing gears; an inclosing case havinga portion in proximate contact with the faces and one of the sides of each of the gears; and a plate in proximate Contact with the other sides of the gears.

25. In a gear engine, the combination of intermeshing gears; a casing inclosing the gears, having an exhaust port and having driving ports on opposite sides of the meshing point of the gears; a supply pipe for conveying driving fluid to the engine; branch pipes connecting the supply pipe with the driving ports; means controlling said pipes, whereby the drivin fluid may be caused to flow into either riving port and out of the other, at will, whereby to reverse the engine; a pipe connected to the branch pipes at their juncture to convey fluid away from the engine; and a pipe connecting the last named pipe with the said exhaust port.

26. In a gear engine, the combination of intermeshing gears; a casing inclosing the gears, having exhaust ports and having driving ports on opposite sides of the vmeshing point of the gears; a supply pipe for the driving fluid; branch pipes connecting the supply pipe with the drivin ports; uid into either branch pipe at will; and exhaust pipes for carrying away the exhaust from the exhaust ports.

27. In a compound gear engine, the combination of intermeshing gears; a easing inclosing the same, having driving and exhaust ports, the driving ports being on op posite sides of the meshing point of the gears; a supply pipe. for. driving fluid, and

means for connecting the same with either driving port atwill; a second set of intermeshing gears; a casing therefor, having driving and exhaust ports, the former being located on opposite sides of the meshing point of the gears; and means for oonveyin exhaust; drivlng fluid from the first set 0' gears to either driving port of the second set at will. i

28. In a compound gear engine the combination of intermeshing gears and a casing ing and exhaust ports, the. former being locat d onopposite sidesof the meshing point of ,he gears; a third set of intermeshing gears and a casing therefor, having similarly located driving ports and an exhaust port; means for delivering exhaust driving fluid from the first set of gears to the second and third sets of gears and to either drivin port the said second and third sets, simu taneously; and means for delivering. exhaust driving fluid from the second set of gears to either driving port of the'third set, simulta= neously with the delivery thereto of exhaust driving fluid from the first set. i

29. In a compound gear engine, the combination of a plurality of sets of inter-meshing gears; casings inclosing the sets of gears, provided with driving and exhaust ports, the driving ports being located on opposite' sides of the meshing points ofthe respective gears; a sup-ply pipe for driving fluid, and means for connecting the same at Will with either driving port of the first set of gears; means for connecting an exhaust port of the first set with eitherdrivin port of the second set at will; and means or delivering exhaust driving fluid simultaneously from the first and second sets to either driving port of the second set.

i. 30. In a compound gear engine, the combination of a plurality of sets of intermeshing gears and casings inclosing the same, having driving and exhaustports, the driving ports being located on opposite sides of the meshing points of, the respective gears; a driving fluid supply pipe, and means for connecting the sameat will to either driving port of the first set of gears; iping for conveying exhaust driving flui from an ex-" haust port of the first set to the second set, and means for delivering driving fluid from said pipe to either driving port of the second set at will; andpiping for conveying exhaust driving fluid from another exhaust port of the first set and from an exhaust port of the second set to the third set, and means for delivering driving fluid from said piping to either driving port of the said third gears, and a va ve for connecting the sup-- ply pipe at will with either driving ort and the exhaust ipe with'the other driving port of the said set; and piping connecting exhaust ports of the first set to the driving ports of the third set, pipes connecting exhaust ports of the second set to said piping, pipes connecting said piping with the drivmg arts of the second set, and valves controlling the flow of driving fluid through said pipes and piping.

32. In a compound gear engine, the comblnation of high, intermediate" and low pressure sets of gears; casin; for the gears, havmg centerpieces provi ed with stationary parts inclcsing the gears about the meshing points of the gears, means for supplying driving fluid to the high pressure set of gears; and means for supplying exhaust driving fluid from the-high pressure set to the intermediate and low pressure sets, and from the intermediate to the low pressure set.

33. In a compound gear-engine, the combination of a plurality of sets of intermesh' ing gears; casings for the gears, having centerpleces composed of stationary parts inclosing the gears about their meshing points and elsewhere leaving space. around the sides and faces of the gears for unimpeded movement of the driving fluid; means for delivering driving fluid to the first set of gears; and means for conveying a portion of the exhaust driving fluidfrom the first set to a succeeding set.

34, In a compound gear en "ne, the combinationof a plurality of setso intermeshing gears; centerpieces for the gears, composed of stationary parts inclosing the gears about their meshing points and elsewhere leaving space around the sides and faces of the gears for unimpeded movement of the driving fluid; the centerpiece for the first set of gears having a driving port and an exhaust port on the same side of the meshing point of the gears and means for conveying exhaust driving fluid from said exhaust port to a succeeding set of gears.

.35. In a compound gearengine, the combination of a plurality of sets of intermeshin gears, and means for utilizin exhaust driving fluid from the first set 0 gears to intense drive a succeeding set and simultaneously counterbalance the driving pressure on the first set.

36. A compound rotary engine of the gear tooth type, having gears that are anly partly inclosed on their sides and faces by the inner construction, for the purpose of directing a fluid pressure medium against the teeth of said gears near their meshing oint; a

high pressure inlet and intermediate and low pressure out-lets; and an'inlet connection to a second set of gears from said intermediate pressure outlet.

37. A compound rotary engine of the gear tooth type, having gears that are only partly inclosed on the sides and faces'by the inner construction, for the purpose of directing a fluid pressure medium against the teeth of said gears near their meshing point; an inlet port and'a plurality of outlet ports with fluid receiving means communicating between the successively lower sets of gears, delivering said fluid-pressure at successively lower pressures to the ports of each respective set of said'gears. I

38; In a device of the class described, the combination of intermeshing gear wheels and a center piece inclosing the sides of said gear wheels adjacentto their meshing points, the.

center piece being made in parts adjustable toward and from each other so as to vary the fit of the parts on the sides of the gears, and means for securing the parts in adjusted position.

39. In a device of theclass described, the

combination of intermeshing gear wheels and acenter piece inclosing the sides of said gear wheels adjacent to their meshing points, the center piece being made in parts adjustable toward and rom each other, and sheets of spacing material insertible .between the parts of the center piece so as to vary the fit of parts of the center piece on thefisides of the gears, and means for securing the parts inadjusted position.

40. In a device of the class described, the combination of a case provided with intake and exhaustopenings, containing intermeshing gear wheels, the gears being 10- catedwithin the case at a substantial distance from the walls thereof, anda normally stationary center piece within the case connected to the intake opening of the case, inclosing the circumferences and having normally stationary side walls inclosing and in approximate contact-with the sides of the gears adjacent to their .iritermeshing points and provided with channels for directing the pressure medium admitted through the intake opening against the teeth of said gear wheels.

41. In a. device of the class described, a fluid tight case having inlet and outlet pipes, a pair of shafts, a gear wheel carried by each the openings in the case, and means, to adjust one of the pieces of the center piece with respect to the other.

In testimony whereof I have set my hand 15 in the presence of the two subscribed witnesses.

CHARLES CLARK.

Witnesses:

FRANK P. MEDINA, AMY E. MEDINA. 

